The pitch diameter is useful in determining the spacing between gear centers because proper spacing of gears implies tangent pitch circles.
12.
It was during this era that more complicated analyses made clear the importance of variables such as pitch diameter and surface finish.
13.
The pitch diameters of two gears may be used to calculate the gear ratio in the same way the number of teeth is used.
14.
For example, a capacity machine can generate gears with a 10 in pitch diameter and usually a maximum of a 10 in face width.
15.
Mics with such anvils are usually called " thread mics " or " pitch mics " ( because they directly measure the pitch diameter ).
16.
A change of center distance is accomplished by changes in operating values for pitch diameter, circular pitch, diametral pitch, pressure angle, and tooth thicknesses or backlash.
17.
Thus, if the pitch diameter of a gear is 40 mm and the number of teeth 20, the module is 2, which means that there are 2 mm of pitch diameter for each tooth.
18.
Thus, if the pitch diameter of a gear is 40 mm and the number of teeth 20, the module is 2, which means that there are 2 mm of pitch diameter for each tooth.
19.
But this requirement alone does not guarantee that a bolt and a nut of the same pitch would fit together : the same requirement must separately be made for the minor and pitch diameters of the threads.
20.
When gear dimensions are in the metric system the pitch specification is generally in terms of " module " or " modulus ", which is effectively a length measurement across the " pitch diameter ".
